#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>

int main()
{
	int arr[10] = { 0 };
	int i = 0;
	int count = 0;
	float result = 0.0;
	for (i = 0; i < 10; i++)
	{
		scanf("%d", &arr[i]);
		count += arr[i];
	}
	result = count / 10.0;
	printf("%f\n", result);
	return 0;
}
